Spanners are frequently hand tools in the mechanic operations. However it is very often that the users must operate the spanner in some complicated conditions so that the users will feel uneasy. This reduces the work efficiency.
Thereby to improve above-mentioned problems, some newly designs are developed. In one improvement, the spanner has a driving head and a holding portion. The driving head is bended with an angle with respect to the holding portion so that the users can operate the spanner in a tilt angle. However in this prior art, the bending angle between the holding portion and the driving head is determined in the manufacturing process so that only little conditions are suitable for this spanner. Furthermore, although it can resolve some problems in the prior art, but it is not so convenient as the prior art straight spanner.
Moreover in another improved structure, the spanner is designed to have a holding portion and a driving head. The driving head is pivotally installed to the holding portion so that when the spanner is operated in some complicated work places, the spanners are bendable to suit the work environment. However this prior art only improves some problems in the prior art, this is because the spanner is only divided into two parts and the rotation angle of the driving head is confined and thus there still are many work conditions which are not suitable to this improved spanner. Furthermore, since only one pivotal structure, the holding portion and driving head cannot be adjusted to be parallel, but not in the same line. Thereby the driving head and the holding portion are not in the same line, and thus the arm of force is small. As a result, the work efficiency is low.